1. Field of the Invention
This invention relates to a machining stabilizer for the mid-span of long cylindrical work pieces.
More particularly, this invention relates to a stabilizer for machines used in cutting cores from long tubular stock.
In general, a number of problems are associated with the machining of long cylindrical work pieces. When machining a long work piece supported at only one end, vibrations and whipping of the free end of the work piece are problems that must be addressed to permit proper machining. When machining a long work piece that is supported at both ends, bowing of the mid-span and vibrations are problems that must be addressed to permit proper machining. When machining a long work piece where the machining is being performed in the mid-span, support against tool thrust and configurations that permit the passage of the tool through the location of the stabilizer are important. When the machining is done at high rotational speeds, the problems are exacerbated.
In general, the mechanisms of this invention can be modified to deal with the problems associated with the machining of a specific long work piece as recited above without departing from the scope of the invention. To apply the stabilizer to a specific task it is necessary to configure the stabilizer to serve the demands of the specific task.
The stabilizer of this invention was developed to stabilize the mid-span of tubular cores being cut on high speed core cutters wherein the method of feeding a new length of core stock involves a head moving along guides to a supply of core stock and acquiring a new length of core stock after which the head is returned to the opposite end of the guides to commence cutting. This process involves the head moving through the location of the stabilizer. The stabilizer of this invention is configured so as to move a pair of stabilizer arms out of the path of the head and return the arms to their operating position once the head has passed their location on the head""s return trip. It is prudent and often required that such machines be fully guarded which adds the requirement that the stabilizer perform its functions within a confined space. Another requirement is that the stabilizer not crush or deform the core and serve to maintain positioning of the core along the centerline of the core cutter while damping out vibrations and suppressing whipping of the free end of the core.
2. Description of the Related Art
The known prior art is replete with steady rests, guides, and backup tools that are positioned in the mid-span of long work pieces that are being machined. Each of these mechanisms has been given specific configurations to serve specific tasks. These prior mechanisms contain some attributes in common with this invention and other attributes that are specific to the task that they are designed to perform. The following patent references represent the prior art most closely related to the stabilizer of this invention.
U.S. Pat. No. 2,958,556 to Samuelson et al. teaches a bottle take out jaw mechanism having a mounting platform, a mover connected to the platform, two arms pivotably connected to the platform, linkages connected to the free end of the mover and to each of the arms and the mechanism operates so that the arms are moved apart as the free end of the mover is advanced towards the work piece. In counter-distinction, the arms of the instant invention are moved apart as the free end of the mover is moved away from the work piece.
U.S. Pat. No. 4,810,019 to Brucher teaches a collet chuck for gripping round objects having two arms pivotably connected to a head, a mover connected to the head, arms pivotably connected to the head, multiple rollers rotatably connected to the arms, and the arms are moved by a multiplicity of links connected to the free end of the mover so that when the rollers are in contact with a cylindrical work piece the work piece is centered between the arms. The apparatus operates to move the arms apart when the free end of the mover is moved towards the work piece.
U.S. Pat. No. 4,754,673 to Hiestand teaches a self centering steady rest that provides adjustments to compensate for elastic deformation of holding members. The holding members move away form the work piece as the free end of the mover moves away from the work piece.
The mover of this invention is self centering and of compact and sturdy construction. The prior art does not teach linkages that connect a mover to arms that are moved away from a work piece when the free end of a mover is moved away from the work piece. Further, the prior art does provide a stabilizer as described, wherein the linkage is such that the arms move through a large angle in response to a short movement of the mover. Further, the prior art does not provide a stabilizer as described wherein the force applied to the work piece by the stabilizer is significantly less than the force present at the free end of the mover.
This invention is for a stabilizer for long cylindrical work pieces comprising: a mounting platform, a mover connected to the platform and the mover has a line of action that is perpendicular to the centerline of the work piece and the mover serves to move a central pivot along the line of action towards and away from the centerline of the work piece, a first arm and a second arm pivotably connected to the mounting platform, and the arms are equally spaced to either side of a plane defined by the centerline of the work piece and the line of action of the mover and the arms project from the mounting platform in the direction of the work piece, and the arms have a length approximately equal to the distance between the platform and the work piece, a first link and a second link pivotably connected to the central pivot and the first link is pivotably connected to the mid-length of the first arm and the second link is pivotably connected to the mid-length of the second arm and the links are angled from the pivot towards the platform, a first roller carrier pivotably connected to the first arm near the end of the arm and on the side of the arm nearest the centerline of the work piece and a second roller carrier pivotably secured to the second arm and on the side of the arm nearest the work piece and the first and second carriers have rotatably secured therein at least two rollers and the rollers are positioned in the carrier so that when the outside perimeters of the rollers are in contact with the work piece the carriers will pivot so that the rollers are in contact with the work piece at equal distances from the centerline of the work piece, and the axes of rotation of the rollers and pivot axes of the pivots are parallel to the longitudinal centerline of the work piece.